Technical Field of the Invention
This invention relates generally to motors, generators, alternators, and the like and more particularly to housing such electronic components.
Description of Related Art
In general, AC induction and brushless DC (BLDC) motors are enclosed using a steel shell or aluminum extrusion. The enclosures or “shells” are manufactured to inner dimension tolerances that are very stringent (e.g., +/−0.001″ diameter). When the shell is made of steel, a second manufacturing operation is needed to prevent rust.
During assembly of a motor, the components of the motor (e.g., stator, rotor, gear boxes, etc.) are secured into the shell using tie bolts, which requires that the shell include internal or external tapped holes or steel nuts. In addition to adding to the cost of the motor and requiring multiple manufacturing operations, the use of steel tie bolts contribute to stator losses.
When an application requires that a motor be submersed, or exposed to, water, then the gears of the motor need to be protected to prevent damage from the water. One approach to protect the gears is to use a urethane as a sealant, which adds to the cost of the motor and adds additional manufacturing operations.